🐞 Unlocking trial project fails on FL's latest version

### Describe the issue

I made a little command line application that should "unlock" a project saved from a trial instance of FL studio. When I run the program and try to re-open the project with FL studio, it crashes, saying "An error occurred while reading the FLP file. It may be corrupted, or some plugin caused an error while opening."

### What version of PyFLP are you using?

2.0.0a7.post0

### What code caused this issue?

```python3
import pyflp
import sys

project = pyflp.parse(sys.argv[1])

project.licensed = True

pyflp.save(project, sys.argv[1])
```

### Screenshots, Additional info

_No response_

### Code of Conduct

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